Electrical connecting device



Sept. 19, 1961 D. L. EYRE ETAL 3,001,170

ELECTRICAL CONNECTING DEVICE Filed July 20, 1959 INVENTOR GLENN H.GLUNTZ BY DENZEL L. EYRE 3,601,170 ELECTRIQAL CUNNECTING DEVICE DenaelL. Eyre and Glenn H. Gluntz, Harrisburg, Pa., assignors to AMPIncorporated, Harrisburg, Pa. Filed July 20, 1959, Ser. No. 828,384 2Claims. (Cl. 339-198) This invention relates to devices for forming acommon junction among a plurality of electrical conductors.

A known type of connecting device comprises a plurality ofterminal-receiving socket members on a common post which is threadedinto a nut. A spring surrounds the post and normally biases theplurality of socket members against the post head so that electrical.

terminals can be inserted into the sockets. The nut which accepts theend of the post has a skirt which is coextensive with the spring so thatif the post is tightened into the nut, the spring is compressed untilthe sockets are clamped between the skirt and the head. Upon suchclamping of the sockets the terminals are themselves securely clamped intheir sockets and cannot be removed. Connecting devices of this typehave proved to be very useful in installations requiring a large numberof common connections which must be permanent and secure againstaccidental disengagement but which must be disengageable to permitcircuit changes.

An object of the present invention is to provide an improved connectingdevice of the above described general type but having means to permit arapid visual determination of whether or not the terminals are clampedin the sockets. A further object is-to provide a connecting device whichpermits the establishment of a plurality of a common junctions on onepost with each of these junctions being electrically insulated from theother junctions on the same post. A further object is to provide a formof socket for terminals of the above described type which has improvedelectrical characteristics.

These and other objects are provided in a preferred embodiment in whicha post extends through a plurality of blocks of conductive metal and isthreaded at its opposite end into an opening in a dielectric block. Thedielectric block provides a bearing surface which faces the adjacentconducting block and against which this adjacent block can be pressed. Acounterboard spacer is interposed between the head of the post and theend of the stack of sockets, and a coil spring is positioned around thepost and bears against the shoulder at the counterbore of the spacer. Byvirtue of this arrangement, when the stack of sockets are onlyresiliently loaded or pressed together by the spring, the spacer isurged against the head of the post but when the post is threaded intothe nut until the spring is fully compressed, this spring is not visibleand it is therefore immediately apparent that the stack of sockets is inits locked condition, i.e. the terminals which are received in thesockets cannot be removed. Whether the sockets are in a locked conditionor whether they are only loosely biased together by the spring is thusimmediately apparent upon inspection of the condition of the spacer. Anadded feature of the invention is that the post itself provides aninsulating surface and dielectric plates are interposed in the stack ofconducting plates to form separate common junctions in the same stack.The entire assembly can be easily assembled and disassembled to provideany combination, within the limits of the number of socket membersprovided, of common junctions for two or more separate conductors.

In the drawings:

FIGURE 1 is a view of the front of a connector module in accordance withthe invention;

FIGURE 2 is a side view of the embodiment of FIG- URE l;

nite States Patent by small upstanding FIGURE 3 is a perspectiveexploded view of the com ponent parts of the preferred embodiment;

FIGURE 4 is a perspective view of a pair of conducting blocks inaccordance withthe invention and a tab of the type which the socketsformed by the blocks are adapated to receive; and

FIGURE 5 is a sectional view showing the lower center section of thedielectric member.

In the preferred embodiment of the invention, there is provided a modulecomposed of insulating material such. as an organic plastic comprising abase portion 2 having a pair of hooks -14- on the separator 10 whichcooperate withshoulders 16 and hooks 18 on the front side of the module.It will be apparent that the hooks l4 wilkwhen a pair of modules aresnapped together, he cammed over the hooks '18 and snapped into theshoulders 16 to lock the parts together.

The post 22 which is threaded into the nut 20 has a threaded end 24, anintermediate portion which has an insulating covering 23, and a head 26which is slotted to receive a screw driver or other tightening tool. The

blocks or socket members 28 which form the sockets for' the terminalshave a central opening 30 through which the screw extends and arebeveled at each end 32 to form openings into which the terminals areinserted. A snap ring 27 is provided on the post to retain the socketmembers in place. The sides 32 of these openings are defined ridgesalong the lateral edges of the blocks! A: central depression 36 in theblocks cooperates with a similar boss on the tab 38 of the terminalwhich is crimped at 40 to the end of a wire 42. As is apparent fromFIGURE 1, each pair of blocks aligned sockets.

Dielectric separators of plastic or the like 44 are interposed betweeneach pair of blocks 28 so that each pair of blocks forms 1 commonjunction for two terminals 38. Obviously any number of these separatorscan be removed to form a common junction for more than two wires. Forexample, if the lowermost dielectric plate 44 were removed from FIGURE1, a common junction would be formed by the four lowermost blocks forfour wires. Above this lowermost junction, two other junctions wouldthen be formed, each capable of accommodating two wires.

Normally the parts would be as shown at the left in FIGURE 2 with thespring 50 disposed around the uppermost portion of post 22 and bearingagainst the counterbored section 39 of a spacer 46. The spring thuspresses the stack of blocks and dielectric spacers downwardly and thespacer 46 upwardly and the shank of the screw is clearly visible. Afterthe desired terminals have been inserted into the sockets, the screw isthreaded into nut 20 until this spring is compressed and the stack ofconducting blocks and dielectric plates are clamped firmly b tweenbearing surface 8 and the spacer 46 as shown at the right in FIGURE 2.

The salient advantage of connecting devices of the instant type is thata completely secure and permanent con nection can be obtained when thestack of sockets or blocks is in its clamped condition and the terminalcan not be removed or the wire disengaged. At the same time, theconnections can be rearranged in any desired fashion by merelyunclamping the assembly to permit easy with- 28 forms two D drawal ofany terminals desired. The instant invention provides a means forimmediate determinationofthe condition of the stack of sockets, that iswhether or not they are clamped. If any part of the shank of the screwis visible, it is apparent that the stack is not clamped, :but if thespacer is obviouslypressed against the uppermost dielectric spacer orplate or the uppermost block 28, it is apparent that the assembly isclamped. A further'advantageot the invention is that any desiredcombination of common junctions for any number of wires, within thelimits of the total numberof sockets provided, canbe provided on asingle clamping post. The-present invention therefore provides a highdegree of versatility and flexibflity capable of satisfying widelydivergent requirements for common junctions.

It will be apparent that electrical separation of the socket blocks 23into several groups is possible in the preferred embodiment by virtue ofthe fact that the spring 59 surrounds the insulated post near the'headthereof rather than at the threaded lower end. By virtuer'of thisarrangement the post 22 is not in conducting contact witl'r'any of thesocket blocks.

It has been found that connecting-devices inaccordance with thepreferred embodiment'have-outstandingly good conducting ability, evenwhen the stack ofconducting blocks are not clamped but are only lightlypressedtogether by the spring. The mating flat surfaces of the-tube andthe blocks are believed to contribute materially in this respect in thatrelatively large intertacial areasbetween. the tabs and block areprovided.

.Changes in construction will occur to those skilled "in the art andvarious apparently different modifications and embodiments may be madewithout departing from the scope. of the invention. The matter set forthin the foregoing description and accompanying drawings is offeredbyway-0i illustration only. The-actualsoope of the invention is intendedto be defined in the followingclaims.

We claim:

1. An electrical connecting device for commonly connecting aplurality ofwires havingtab type terminals on their ends comprising, a supporthaving=a threaded opening therein and bearing surface adjacentsaidopening, a post having one threaded end extending into said openingandhavinga head at its opposite end, the -intermediate portion of saidpost having an electrically insulated'surface, a plurality of pairsofconducting ,blocks having aligned central openings instackedrelationship on said post with said post extending through saidopenings, dielectric plates separating at least some of said pairs ofsaid conducting blocks from other pairs of said blocks, a counterboredspacer member interposed between said head of said post and the blockimmediately adjacent said head with the counterbore of said spacerfacing said adjacent block, and a coil spring within said ceunterboreand bearingagainst said spacer member and said adjacent block whereby,upon rotation of said screw with concomitant movement thereof into saidthreaded opening, said spring is compressed until said blocks aresecurely clamped between said spacer and said bearing surface and tabterminals positioned between adjacent blocks are securely clamped.

2. An electrical connecting device for connecting a plurality of wireshaving terminals on their-ends comprising, a support having a threadedopening therein and a bearing surface adjacent said opening, a posthaving a threaded end extending into said opening and having a head atits opposite-end, a plurality of pairs of conducting socket membershaving aligned openings intermediate their ends, said post extendingthroughsaid socket members, a spacer having'a central'bore and acounterbore surrounding said post, acoil springsurrounding said post andextending into said counterbore, saidcoil spring being efiective betweensaid spacer and one of said socket members whereby, upon insertion of anelectrical terminal into one of the sockets formed by said socketmember, said terminal is resiliently clamped by virtue of said spring,and upon rotation of'said screw, said spring is compressed until saidsocket members are clamped between said spacer and said support andrigidly clamp said terminal.

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